I have 8.5 on the front with 235/35/19, alloys are ET30 with a 3mm spacer to clear the brembo's, they barely fit and i get rubbing on the front arch liner in really bad roads, some people have also expierenced the inside tyre wall rubbing on the shocks to depending on what coilovers they have fitted. I have a set of 225/35/19 tyres on the way to
help reduce the rubbing but they will have a slight stretch on them.I will still have my 8.5j 235/35/19 on the back but i will lower my car a few more MM and add bigger spacers to get a nicer stance. If i had my time again, i would have 8 up front and 9 rear.
It works taking in consideration that some 19" alloys, especially reps are much heavier than the OEM LCR aloys and increase your grip but will also affect your performance.